This research addresses two long-neglected areas of narcotic action: specific effects on intestinal motility and central actions which affect peripheral organ function. Our techniques allow separation of central and peripheral sites of narcotic action in unanesthetized animals. The mechanisms by which narcotics produce their acute effects, mechanisms of tolerance and mechanisms of withdrawal effects on intestinal motility are of great fundamental interest and of importance in the human pharmacology of the narcotics. Results of these studies will be of value in management of addiction and in drug therapy of gastrointestinal diseases.